I would think it's the large flag because it symbolizes a nation's pride.
In the opening scene, death is trying to gain the reader's trust by talking to him/her as if it were a human being. The reader becomes confused at the beginning and then starts to accept the fact that death is a natural occurrence.
Death is showing the reader that it was very busy during World War II.
By the end of this scene, death managed to introduce itself as a main character and a reliable narrator for the book.
Greet means giving a polite word or sign on welcome to someone.
